Good question. I think moving to the Kinvara as your road shoe would make a lot of sense if you love the Peregrine.
I actually started with the Kinvara (fell in love!), and then decided to try the Peregrine after having a conversation with a Saucony rep about the similarities. The Peregrine and Kinvara are made on the same “Last,” so the fit is consistent. Also, the heel-to-toe drop is the same between the two.
I have a friend here in Nashville that got back into running last year after taking some time off. He was running a lot of trails, and hated his shoes, so I suggested he try the Peregrine. He also fell in love with them, and then moved to the Kinvara for his road shoe. He loves both of them.
Also, Nathan (who I mention in a LOT of my posts) and I both use the Kinvara as our road shoe and Peregrine as our trail shoe. I don’t think either of us have any intention of changing in the near future.
Hope this helps!